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CERF Underwater video from Jervis Bay

Note: This metadata describes the dataset in accordance with the ANZLIC (Australia New Zealand Land Information Council) Core Metadata Guidelines Version 2.


Dataset citation

ANZLIC unique identifier: ANZCW0703015197

Title: CERF Underwater video from Jervis Bay


Custodian

Custodian: Geoscience Australia

Jurisdiction: Australia


Description

Abstract:

Geoscience Australia carried out marine surveys in Jervis Bay (NSW) in 2007, 2008 and 2009 (GA303, GA305, GA309, GA312) to map seabed bathymetry and characterise benthic environments through co-located sampling of surface sediments (for textural and biogeochemical analysis) and infauna, observation of benthic habitats using underwater towed video and stills photography, and measurement of ocean tides and wave-generated currents. Data and samples were acquired using the Defence Science and Technology Organisation (DSTO) Research Vessel Kimbla. Bathymetric mapping, sampling and tide/wave measurement were concentrated in a 3x5 km survey grid (named Darling Road Grid, DRG) within the southern part of the Jervis Bay, incorporating the bay entrance. Additional sampling and stills photography plus bathymetric mapping along transits was undertaken at representative habitat types outside the DRG. The GA0309_0312_JervisBay2008 folder contains video footage; the GA0326_JervisBay2009 folder contains still images; and the files are the video characterisation datasets. Underwater towed-video footage and still images represent the raw data. Video characterisation datasets include substrata types and the presence/absence of benthic taxa.

ANZLIC search words:

  • GEOSCIENCES Mapping
  • MARINE

Spatial domain:

locality map

Geographic extent name: AUSTRALIA EXCLUDING EXTERNAL TERRITORIES - AUS - Australia - Australia

Geographic extent polygon: 150 -34.5, 151 -34.5, 151 -35.5, 150 -35.5, 150 -34.5,

Note: The format for each Geographic extent name is: Name - Identifier - Category - Jurisdiction (as appropriate) See GEN Register

Geographic bounding box:
North bounding latitude: -34.5 °
South bounding latitude: -35.5 °
East bounding longitude: 151 °
West bounding longitude: 150 °

Data currency

Beginning date: 2008-06-17

Ending date: 2008-06-17


Dataset status

Progress: Complete

Maintenance and update frequency: Not Known


Access

Stored data format:
DIGITAL - xls Microsoft Excel spreadsheet Excel
Available format type:
DIGITAL - xls Microsoft Excel spreadsheet Excel

Access constraints:

This material is released under the Creative Commons Attribution 3.0 Australia Licence.

Free Data Download

Data quality

Lineage:

Two video surveys were conducted during the 17-20th June 2008 (GA survey #0312) and 25-26th August 2008 (GA survey #0309) in the Darling Road survey area. In addition, a drop-camera survey was conducted during 23 - 26 November 2009 to collect still colour photographs of the seabed at 24 stations across Jervis Bay. To map the spatial distributions of benthic habitats and biota within the Darling Road grid, video transects were run alongshore (4x 6km-long transects) and offshore (6x 3km-long transects) using Geoscience Australias shallow-water Raytech towed-video system. The initial survey was undertaken during the 17-20th, June 2008 (early Australian winter) as part of the acceptance test of the new towed-video system (GA Survey No. GA312). During this time we successfully collected 6 offshore transects and 1 of the 4 alongshore transects. A follow-up survey two months later on 25-26th August 2008 completed the remaining 3 alongshore transects (GA Survey No. GA309). The towed-camera system housed a forward-facing video camera and associated lights, and was deployed from the stern of the MV Kimbla and towed at 0.5 to 1.5 knots. A rope capstan was used to maintain the video system at an altitude of 0.5 - 2 m above the seabed, while a coaxial cable transmitted video footage to the ships video monitor where it was characterised in real time by the observer and similtaneously recorded to mini DV tapes, which were later copied to digital format. Seabed characterisations were recorded in real-time every 30 seconds along each video-transect using the 3-tiered characterisation scheme of substratum composition, bedform-relief, and biota presence described in Anderson et al. (2008). A 15-second period (i.e. 5 seconds prior to and 10 seconds following the GPS fix) was evaluated to characterise the seabed. Seabed characterisations were entered in GNav Real-time GIS Tracker software ( Gerry Hatcher, 2002) using a 142 key Cherry programmable keyboard (Cherry, 2008). For each data entry location, the GPS captured ships navigation (UTC date, time, latitude, and longitude). Data entry took between 3-12 seconds, and required a two-person team (i.e. observer and data-enterer). Substrata composition (i.e. rock, boulders (greater than 25.5cm), cobbles (6.5-25.5 cm), sand, and mud) was categorised by primary (greater than 50% cover) and secondary (greater than 20% cover) percent-cover following the earlier protocol of Stein et al. (1992) and Yoklavich et al (2000).

Positional accuracy:

There is a position accuracy/uncertainty of approx. 20 m. The gps location of transects was recorded using the MV Kimba GPS system (ie Shipboard navigation). Using ship board navigation means that there is some uncertainty as to the position of the towed-video system behind the ship. There is an estimated 5-20 m uncertainy in position based on the angle and length of tow wire deployed behind the ship and water depth. This positional uncertainty can not always be assumed to be directly behind the ship as current and winds often place the towed-video system at an angle to the ship

Attribute accuracy:

Substrata and relief variables are recorded following a clear set of definitions following the protocol of Anderson et al., (2008). Substrata composition (i.e. rock, boulders (greater than 25.5cm), cobbles (6.5-25.5 cm), sand, and mud) was categorised by primary (greater than 50% cover) and secondary (greater than 20% cover) percent-cover following the earlier protocol of Stein et al. (1992) and Yoklavich et al (2000). Bedform-relief was defined as either soft-sediment bedform such as hummocky, sediment ripples, or sediment waves, or by the vertical relief of consolidated sediments: relief classes ranged from flat (0 m), low (less than 1 m), moderate (1-3 m), to high relief (greater than 3 m), or rock walls (high-relief with greater than 80 degree incline). Biota composition was described by recording the presence of benthic macro-organisms identified to broad ecological categories (e.g. sponges, ascidians, crinoids, red algae, brown algae, etc.), genera (Ulva) and species (e.g. Neoodax balteatus (common odacid wrasse)) (see Anderson et al., 2008 for more detailed methods). Variable height off the seafloor and water clarity (turbidity) may influence the degree of certainty/uncertainty in regards to the absence of some biota variables (not seen but were present), especially those that are small (e.g. small crinoids), found in the sediments (polychaete worms), or maybe covered by algae (e.g. polychaete trees). However, the accumulation of data points along each transect should provide a good representation of the epibenthic assemblages present in these habitats. Consistency in seabed characterisations was ensured by having one observer (Dr. Tara Anderson). Data have undergone preliminary QA/QC (15% of the dataset randomly checked (Dr Tara Anderson and Ms Maggie Tran), and were deemed fit for purpose (less than 5% error rate), but a data check of all records has not been undertaken. The definitions of the attributes and their values can be found in JBay_Metadata_attributes.xls and definitions.xls

Logical Consistency:

All video footage was processed in real time following the protocol of Anderson et al., (2008) and outlined in GAs video acquisition protocol. This method is the standard method used to acquire seabed characterisations as part of bio-physical mapping surveys at Geoscience Australia, and as such has been used for a range of GA and CERF surveys (e.g. CERF SE Tasmania survey)

Completeness:

Complete


Contact information

Contact organisation: Commonwealth of Australia (Geoscience Australia) (GA)
Contact position: Manager Client Services
Mail address: Cnr Jerrabomberra Ave and Hindmarsh Dr
Mail address: GPO Box 378
Locality: Canberra
State: ACT
Country: Australia
Postcode: 2601
Telephone: 02 6249 9966
Facsimile: 02 6249 9960
Electronic mail address: sales@ga.gov.au

Metadata information

Metadata date: 2013-03-08


Additional metadata

Metadata reference XHTML: http://www.ga.gov.au/meta/ANZCW0703015197.html

Metadata reference XML: http://www.ga.gov.au/meta/ANZCW0703015197.xml

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Authors:Geoscience Australia
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